Senior Kotlin Backend Engineer

Our Company

At Contiant, we’re building the future of open banking payments. Based in Sofia, Bulgaria, we provide fast, reliable, and secure payment initiation and account information services across the EU.

Our mission is simple: make payments smoother than credit cards and give merchants full control of the payment experience—without compromising conversion, speed, or security.

We’re developers at heart, building an API-first platform that delivers both power and elegance. Our systems combine cutting-edge technology with solid engineering principles, so every service is robust, scalable, and built to last.

The Role

We’re looking for a Senior Backend Engineer to help craft modern, high-performance services that power Contiant’s platform. You’ll own features end-to-end—from design discussions to deployment—and help shape how we build software.

You’ll collaborate with a cross-functional team of engineers, product owners, and designers, making thoughtful technical decisions and mentoring others along the way.

What You’ll Do

– Design, build, and maintain scalable microservices using Kotlin (or Java if you’re ready to switch).

– Own the full lifecycle of features: architecture, implementation, testing, deployment, and operations.

– Collaborate with Product, Frontend, and BI teams to build reliable, user-focused financial products.

– Mentor mid-level engineers and promote engineering excellence.

– Continuously improve system performance and maintainability through incremental, high-impact changes.

– Advocate for best practices in code quality, Gradle optimization, and development workflow.

– Work with modern infrastructure and tools including Kafka, RabbitMQ, Kubernetes, Docker, and AWS.

– Contribute to our DevOps culture by applying CI/CD principles and maintaining observability.

What We’re Looking For:

– 4+ years of backend experience using Kotlin or Java (if you are ready to move to the better language)

– Experience with Ktor and/or Spring frameworks.

– Understanding of transactions and isolation levels in relational databases.

– Hands-on experience with PostgreSQL and strong knowledge of SQL.

– Experience with event-driven architectures using Kafka.

– Solid understanding of reactive programming principles (e.g., Proactor pattern, Mono/Flux, R2DBC).

– Familiarity with CI/CD pipelines and DevOps practices.

– A pragmatic problem-solver who prefers improving existing systems over full rewrites.

– Strong communication skills and a collaborative mindset.

– Upper-intermediate English proficiency (both written and spoken).

Why Join Us

At Contiant, you’ll work on meaningful problems that impact real people and businesses. You’ll have the freedom to experiment, the tools to build high-quality systems, and a team that values both craftsmanship and simplicity.

If you love writing clean, maintainable code and building systems that scale, we’d love to hear from you.